Adjustable motor-driven hospital bed having a housing for part of the bed superstructure

ABSTRACT

A bed, more particularly a hospital bed comprises a bedstead (1), preferably with casters (12) and a bed superstructure (2) mounted in the bedstead (1) in a vertically adjustable manner, with a preferably adjustable bed frame. In order to ensure that such a bed with a simple structure may have a pleasing appearance, the head part and/or the foot part of the bed superstructure (2) is provided respectively with at least one downwardly directed telescoping rod (15), which runs respectively in an associated telescopic guide of the bedstead, the telescopic guides of the head part and respectively of the foot part being respectively surrounded by one piece of cladding (9 and 10).

FIELD OF THE INVENTION

The invention relates to a bed and more particularly to a hospital bedcomprising a bedstead and a bed superstructure mounted on the bedsteadin a vertically adjustable manner and having a preferably adjustable bedframe.

BACKGROUND OF THE INVENTION

A hospital bed of this type is disclosed in the German utility model9,207,352.

Furthermore the U.S. Pat. No. 2,827,641 discloses a hospital bed in thecase of which the bed superstructure is connected with four verticaltelescoping tubes of essentially square cross section, in each of whicha respective telescoping rod is arranged for longitudinal slidingmovement. Each telescoping rod is provided with a caster at its lowerend. By means of a motor all telescoping rods may be simultaneouslyextended. The motion of all four telescoping rods is however ganged sothat it is impossible to change the slope of the bed superstructure.

The U.S. Pat. No. 2,747,203 discloses a hospital bed which comprises abed superstructure with an adjustable bed frame. Both the head part ofthe patient support surface of the bed frame and also the foot part ofthe patient support surface of the bed frame are adjustable, each bymeans of a separate motor. The motors are connected with the bedstead.

The U.S. Pat. No. 2,819,474 discloses a similar hospital bed in the caseof which also the bed frame is provided with an adjustable patientsupport surface, both the head part of the patient support surface andalso the foot part of the patient support surface being able to beadjusted by a respective separate motor.

The prior art mechanisms for vertical adjustment involve certaindisadvantages. In part very elaborately designed adjustment mechanismsare provided. In other cases the bed has a generally ugly appearance.

BRIEF SUMMARY OF THE INVENTION

One object of the present invention is to provide a verticallyadjustable bed and more especially a hospital bed, which whilepossessing a simple structure also possesses a generally pleasingappearance.

The head part and/or the foot part of the bed superstructure is providedwith at least one downwardly directed telescoping rod running in arespective associated telescopic guide of the bedstead, the telescopicguide of the head part and, respectively, of the foot part beingsurrounded by cladding. Accordingly the bed possesses both a simplestructure and also an agreeable appearance.

The arrangement of the telescoping tubes and of the telescopic guidesmay also be reversed: then the head part and the foot part of the bedsuperstructure are each furnished with at least one downwardly extendingtelescopic guide, in which the associated telescoping rods of thebedstead run.

Further advantageous developments of the invention are defined in thedependent claims.

It is an advantage if the cladding is designed in the form ofself-supporting cladding. In the case of designs so far known thebedstead, which carries the load bearing part, is encircled by separatecladding. On the other hand in the present case, in accordance with theadvantageous further development of the invention, the cladding isdesigned in the form of self-supporting cladding. This self-supportingcladding simultaneously performs two functions: on the one hand thefunction of carrying the bed superstructure and on the other hand thefunction of cladding the parts necessary for vertical adjustment.

Preferably the cladding members are designed in the form of housings. Itis also an advantage if the housing is designed as a housing which isclosed on all sides. It is more particularly an advantage if the housingis in the form of a cast housing, and preferably as an aluminuminjection casting or a magnesium injection casting. Since the housingsare shut off on all sides, it is a simple matter to clean the same. Thisis something of particular importance, if the bed is used as a hospitalbed or as a bed for home care, both for hand cleaning and also formechanical cleaning in a cleaning apparatus or cleaning plant. Suchspecial purpose cleaning plant for hospital beds have already beenproposed. In this case the beds are placed in a cleaning chamber andautomatically or manually cleaned, something which may be performedusing superheated steam and/or chemical cleaning materials and/or othercleaning devices such as brushes and the like. The housing, which isclosed in on all sides can be made water-tight in a simple manner. Itmay furthermore be designed in the form of a completely encapsulatedhousing. The moving telescoping rods extending out from the housing mayhave seals between them and the housing, for example in the form of anannular seal preferably in the form of a shaft seal. The housing, whichis preferably closed on all sides may furthermore be designed asself-supporting cladding. It is an advantage moreover if the drive motorfor the movement of the telescoping rod or, respectively, thetelescoping rods is arranged within cladding or, respectively, withinthe housing. It is however also possible to arrange the drive motoroutside the housing. If the bed is to be suitable for automaticcleaning, then in this case a water-tight motor must be employed.

The housing can be made in two parts. This is more especially anadvantage if it is a question of a cast housing. On the mutuallyopposite surfaces of the two parts a housing seal may be provided,preferably by a sealing material, which is applied during assembly, asfor instance silicone compound or another plastic sealant. Cast housingspossess the further advantage of being able to be sealed in a simplefashion.

A further advantageous development of the invention is characterized inthat the components required for the operation of the telescoping rodsand any casters are arranged within the cladding or, respectively, thehousing or cast housing. This means that on the one hand the exteriorappearance is still further improved while on the other hand thepossibility of cleaning is enhanced, since only the cladding must becleaned and the parts located therein are no trouble. It is possible forstill further parts to be installed in the cladding.

Preferably the cladding at the head end and the cladding at the foot endis connected together by at least one connecting member designed in theform of a connecting tube. This means that there is a particularlysimple and light construction. The German utility model 7,117,979discloses a traveling hospital bed, in the case of which the bedsteadpossesses a cast part. This cast part is however open in a downwarddirection, that is to say not shut off on all sides and can thereforenot be simply cleaned. The cast part furthermore covers over the entireextent of the bed. It is consequently heavy, difficult to handle anddifficult to manufacture and furthermore expensive. As compared with thedesign of the said German utility model 7,117,979 with a single largecast member, the said further development of the invention, in additionto being shut off on all sides, does offer the advantage that it iseasier to produce and to assemble. The cast housings provided inaccordance with the invention may be designed to be substantiallylighter in weight and smaller in size. They are connected together bythe connection part. The unit constituted by the cladding and housingsand the connecting part may be termed an under-carriage.

The connecting parts or, respectively, connecting tubes are preferablymanufactured of extruded section and more particularly of aluminumextruded section or magnesium extruded section. The employment of aconnecting tube or of another connecting part with a closed crosssection offers the advantage that then the entire under-carriage may besimply cleaned. Moreover, the under-carriage may be designed with apleasing exterior shape.

In accordance with a further advantageous development the inventioncontemplates the provision of a force transmitting element on or in aconnecting part for the setting of the casters. Such force transmittingelement is preferably a shaft. It is preferably advantageous if theconnecting part is designed in the form of a connecting tube. The forcetransmitting element is then located in the connecting tube, where it isnot visible and does not get in the way of cleaning. Furthermore, it isprotected against blows and dirt etc. from the outside and functionaltroubles are prevented.

A further advantageous development is characterized in that thetelescoping rod or, respectively, the telescopic rods is or are arrangedoutside the line connecting the casters. Preferably the cladding or,respectively, the housing has an angled part in its terminal regions.Both possible designs are more particularly an advantage, if the castersprovided on one cladding part can be set and if they are connectedtogether by a force transmitting element. The force transmitting elementis preferably designed in the form of a straight shaft. The telescopingrods are placed outside the connecting line between the casters and areaccordingly outside the shaft so that the stroke of the telescoping rodsis not obstructed by the shaft. Accordingly it is possible to providethe full stroke for the telescoping rods.

Preferably the connecting line between the casters is on the side of thetelescoping rods facing away from the middle of the bed. In this casethe cladding is outwardly angled in its terminal region as seen fromabove. Accordingly the rectangle described by the four casters of thebed is larger so that the surface on which the bed stands is larger andthe bed is more stable than in the opposite case in which the connectingline of the casters is on the side, facing the middle of the bed, of thetelescoping rods.

In accordance with a further advantageous embodiment the head part andthe foot part of the bed superstructure is provided with respectivelytwo parallel, spaced, downwardly directed telescoping rods, which run inassociated telescopic guides of the bedstead. Preferably the distance ofthe casters from one another is larger than the distance of thetelescopic guides from each other. Since respectively two telescopingrods are present, there is the advantage over a design with only onetelescoping rod that the telescoping rods may be made smaller in size,something ultimately meaning that costs will be lower. Furthermorestability is increased. Because the telescoping rods and, respectively,telescopic guides are not placed over the wheels and the associatedrecesses in the housing, the path available for outward telescopingmovement is increased, something which reduces the overall height of thebed or, for a given overall height, increases the stroke available foroutward telescoping at a given overall height. Since the wheels are onthe outside, stability of the entire bed is increased when wheeling thebed along and also there is also an increase the stability of the bed inthe upright position.

Preferably a separate drive motor is provided both for the head part ofthe bed superstructure and for the foot part of the bed superstructure.Since the motors for the head part and the foot part of the bedsuperstructure are able to be operated separately and independently fromone another, the bed superstructure may extend both horizontally andalso at a slope (in the so-called Trendelenburg position).

Preferably the telescoping rods of the head part and/or of the foot partare connected together by one respective transverse member. Thetransverse member preferably extends substantially horizontally. Thetransverse member increases the stability of the arrangement.

A still further embodiment of the invention is characterized in that thetelescoping rods are each provided with a lead screw drive able to bedriven from a common toothed belt. Instead of this, by way of akinematic reversal of parts, the telescopic guides may each be providedwith a respective lead screw drive. Furthermore, instead of the toothedbelt it is possible to provide some other flexible force transmittingelement, which also ensures synchronous running of the lead screwdrives, as for instance a chain. The use of such a force transmittingelement offers the advantage that the drive possibility for the verticalmovement of the bed superstructure may also be produced when the bedsuperstructure is inclined in a simple fashion and reliably, sinceequalization of angles is possible in a simple and reliable manner.

Preferably the casters are arranged to be locked by a locking element.The setting members for the casters are preferably arranged in thecladding. It is furthermore an advantage if all casters may be arrestedand released using a single locking member. The setting member ispreferably able to be operated from either side of the bed.

It is an advantage if one motor is provided for operation of the lockingelement or, respectively, the setting members. Preferably it is here aquestion of an electric motor. It is an advantage if manual operation ofthe locking element or, respectively, the setting members is alsopossible.

As part of a further advantageous development of the invention thecladding is lower in the part between the telescopic guides than thetelescopic guides. For instance components may be present on the lowerside of the bed superstructure without this meaning that verticalmovement is reduced.

A further advantageous development is characterized in that the castersare able to be moved into a first position (wheeling position), in whichthey are able to be freely rotated and in a second position (lockedposition) in which they are locked. The motor will be preferably anelectric motor. Owing to the possibility of motor-powered setting ofcasters handling of the hospital bed is improved.

A still further development of the invention contemplates that thecasters are adapted to be brought into a third position, in which atleast one caster may be wheeled while keeping its direction and in whichthe other casters are able to be rotated freely. The caster able to bewheeled but held to keep to its direction, is preferably in this casealigned with the longitudinal direction of the bed. This third positionis then the so-called straight ahead setting, in which the bed may bewheeled along aligned with its longitudinal direction.

A further advantageous further development is characterized in that themotor is able to operate, or more particularly turn, a first forcetransmitting element, more particularly a shaft, such element beingconnected with a caster.

Preferably an operating part is provided for manually changing theposition of the casters. The casters may then be set selectivelymanually set using the operating part or by the power of the motor. Theoperating part may furthermore be designed in the form of an operatinglever or as a pedal or double pedal. The possibility of manual settingso created is then more particularly significant, if the motor is unableto be operated, for example because no power supply is present foroperation of the motor or because the motor has a defect.

It is an advantage if the actuating part is connected with the firstforce transmitting element or, respectively, the shaft.

It is also an advantage if the operating part is connected with thefirst force transmitting, or with the shaft by a clutch. This is moreparticularly significant if an operating part or, respectively, anoperating lever or, respectively, pedal is present for manually changingthe position of the casters and if the operating part is connected withthe first force transmitting or, respectively, with the shaft. Then themotor or, respectively, the parts connected with it would prevent manualadjustment of the casters; owing to the clutch the mechanical connectionwith the motor is interrupted and a manual adjustment of the casters isrendered possible and may be performed as desired.

Preferably the clutch possesses a first hub and a second hub which areconnected allowing the possibility of disconnection. The first hub isable to be operated by the motor. The second hub operates the firstforce transmitting means or, respectively, the shaft. It is advantageousif the hubs are loaded by spring means toward each other.

The motor can be connected with the clutch or with its first hub bymeans of a transmission, as for example a spur gear wheel drive of aworm gear wheel drive.

A further possibility is characterized in that the first forcetransmitting element or, respectively, the shaft is connected with twocasters. This means that the settings of the two casters may be gangedtogether in a simple fashion.

In keeping with a further advantageous feature of the invention on thehead part of the bed and on the foot part thereof respectively twocasters are provided, which are connected together by a respective firstforce transmitting element or, respectively, a shaft and further the twofirst force transmitting elements or, respectively, the shafts areconnected by a second forcing transmitting element. All casters may thenbe set or turned by a single motor simultaneously. The second forcetransmitting element may also be designed in the form of a shaft. It mayfurther be arranged in a tube connecting the head part of the bed withthe foot part of the bed and accordingly be clad in a simple manner.

A still further development is characterized in that the telescoping rodor, respectively, the telescoping rods is or are arranged outside theconnecting line between the casters. Preferably the cladding or,respectively, the housing has an angled part in terminal parts thereof.Both possibilities are then more particularly an advantage if castersprovided on one cladding part may be set and if they are connected by aforce transmitting element. The force transmitting element is preferablydesigned in the form of a straight shaft. The telescoping rods arearranged outside the connecting line between the casters and accordinglyoutside the shaft so that the stroke of the telescoping rods caused bythe shaft is not obstructed. Accordingly it becomes possible toguarantee the full stroke of the telescoping rods.

Preferably the connecting line between the casters is on the side, whichfaces away from the middle of the bed, of the telescoping rods. In thiscase the cladding is angled in its end regions that is to say angledoutward as seen from above. Accordingly the rectangle described by allfour casters of the bed is larger so that the area on which the bedstands is larger and the bed is more stable than in the converse case,in which the connecting line between the casters is on the side of thetelescoping rods facing the middle of the bed.

Working embodiments of the invention will now be described in detailwith reference to the accompanying drawings.

BRIEF SUMMARY OF DRAWING

FIG. 1 shows a hospital bed in a side elevation.

FIG. 2 shows the hospital bed of FIG. 1 in a front view.

FIG. 3 shows the hospital bed in a diagrammatic plan view.

FIG. 4 shows a patient supporting insert for the hospital bed.

FIG. 5 shows a part of the hospital bed in a lateral elevation.

FIG. 6 is a view of part the structure of FIG. 5 on a larger scale.

FIG. 7 shows a circuit diagram for the control of the verticaladjustment of the hospital bed.

FIG. 8 shows a caster operated by a shaft with a clutch in a plan view.

FIG. 9 shows the arrangement of FIG. 8 in a lateral elevation.

FIG. 10 shows a modified embodiment of the invention in a plan view.

FIG. 11 shows the arrangement of FIG. 10 in a lateral elevation.

FIG. 12 depicts a further embodiment of a bedstead with casters in alateral elevation.

FIG 13 shows the bedstead of FIG. 12 in a front view with thetelescoping rods extended upward.

FIG. 14 shows the bedstead of FIGS. 12 and 13 in plan view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The hospital bed depicted in FIG. 1 comprises a bedstead 1 and a bedsuperstructure 2 mounted thereon for vertical adjustment in heighttogether with a bed frame, not illustrated in FIG. 1, which possesses apatient support surface. The bed frame 2 possesses side parts 3 (bedsides) and corner posts 4.

The bedstead 1 comprises head end cladding 9 and foot end cladding 10,such cladding parts being joined together by frames 11. On the outerends of the cladding 9 and 10 casters 12 are provided.

The cladding 10 is represented partly in section. It has two parallel,spaced, vertical telescopic guides 13 and 14, in which a respectivevertical telescoping rod 15 and 16 runs longitudinally. The telescopingrods 15 and 16 are connected together with each other at their upperends by a horizontal transverse member 17, on which the bedsuperstructure 2 is rested (not illustrated in FIG. 2).

The telescoping rods 15 (and also the remaining telescoping rods) has aslip ring 18 of an anti-friction material at its lower end, suchmaterial or coating having its outer surface running against the innersurface of the telescopic guide 13. On the upper end of the telescopicguide 13 (and also of the remaining telescopic guides) a further slipring 19 is provided, which is also manufactured of anti-frictionmaterial and has its inner surface running against the outer surface ofthe telescoping rod 15. In the interior of the telescoping rod 15 a leadscrew 20 is provided which is able to rotate but is held against axialmovement. The lead screw 20 extends through a nut 21, which is connectedby a vertical sleeve 22 with the bottom 23 of the cladding 10.Accordingly the lead screw and with it the telescoping rod 15 may bemoved upward and downward by rotation of the lead screw 20 in relationto the nut 21 and therefore in relation to the cladding 10.

For this purpose the transverse member 17 has an electric motor M2attached to it, which drives a belt pulley 25 around which a toothedbelt 26 is trained. The toothed belt is trained around bend pulleys 27at its untoothed side in a direction parallel to the transverse member17. It is trained around gear wheels 28 and 29 which are respectivelyconnected with the telescoping rods 15 and 16 and are mounted coaxiallythereon. The gear wheels 28 and 29 are able to be rotated in relation tothe associated telescoping rods 15 and 16, but however are held againstaxial displacement. Furthermore the gear wheel 28 (and accordingly alsothe gear wheel 29) is connected with the associated lead screw 20 sothat the rotation of the gear wheel 28 is transmitted to the lead screw20. When the motor M2 is operated, the gear wheels 29 and 29 are drivensynchronously and accordingly the telescoping rods 15 and 16 are movedsynchronously upward or, in the case of the opposite direction ofrotation of the motor M2, downward.

On the transverse member 17, as indicated in FIG. 1, a further motor M1is attached, which via the connecting shaft 30 and the belt pulley 31and furthermore the toothed belts 32 and the gear wheel 33 as well as afurther gear wheel to the rear in terms of FIG. 1 moves the twoparallel, vertical, spaced telescoping rods upward or downward. Thecladding 9 is designed in the same manner as the cladding 10. The sameapplies for the associated telescoping rods, of which FIG. 1 only showsthe front telescoping rod 34.

The motors M1 and M2 are accommodated or encapsulated in a sealed,water-tight housing 35. Accordingly the hospital bed may be rapidly andreadily cleaned, The housing 35 is protected against sprayed or splashedwater and/or against other harmful-effects of the environment.

As shown in FIG. 1, the housing 35, in which the motors M1 and M2 areencapsulated, is located on the foot part of the bed or, respectively,of the bed superstructure. Here it least interferes with the operationof the bed. Furthermore there is the added advantage linked to this thatthe electromagnetic fields of the electric motors are produced at apoint such that the patient is not likely to be harmed by them. Becausethe electric motors M1 and M2 are encapsulated in a housing 35 thefurther advantage follows that the wiring for the electric motor M1 andM2 is simple.

The housing 35 is connected with the transverse member 17 joining thetelescoping rods 15 and 16. Accordingly the housing is moved togetherwith this transverse member 17 and therefore together with thisassociated foot part of the bed superstructure 2 upward and,respectively, downward.

In FIG. 4 the patient support surface 36 in shown, which comprises fourparts connected together in an articulating fashion, i. e. the head part37, the middle parts 38 and the foot part, which for its part includestwo part 39 and 40. The patient support surface 36 may for example beconstituted by an array of slats or however may be in the form ofintersecting bars or in some other form.

For the patient support surface 36 two possibilities of adjustment areprovided for. In the housing 35 an electric motor 41 is arranged, whichis adapted to turn a lead screw 42 extending through a nut 43. The nut43 is connected with a tube 44, running longitudinally in a hole 45 inthe guide tube 46. The nut 43 is connected with the guide tube 46 forlongitudinal movement therein while being prevented for rotating inrelation to it.

On the end of the tube 44 remote from the nut 43 the one arm 47 of atwo-armed lever is pivoted, whose other arm has its outer end 49 bearingon the lower side of the head part 37. The two-armed lever 47 and 48 ispivoted on the outer end of a connecting rod 50 about a pin 51. Theother end of the connecting rod 50 is connected with the electric motor41 or, respectively, with its housing.

Owing to this arrangement the reaction forces occurring on operation ofthe head part 37 are not transmitted to the bed superstructure but aretaken up by the connecting rod 50, which on the one hand is connectedwith the electric motor 41 and on the other hand with the pivot pin 51of the two-armed lever 47 and 48. Rotation of the electric motor 41 isconverted into rotation of the lead screw 42 with the result that thenut 43 and with it the tube 44 are moved in the direction of the doublearrow 52. Accordingly the two-armed lever 47 and 48 is pivoted about thepin 51 so that the head part 37 of the patient support surface 36 may bepivoted upward or downward. The forces transmitted by movement of thetube 44 to the lever 47 and 48 and taking effect on the head part 37 ofthe patient support surface 36 are not transmitted to the bedsuperstructure. Instead such forces are taken up by the connecting rod50 and transferred by same back to their point of origin so that theforce transmission path is completed without affecting or including thebed superstructure and accordingly without having any effect on the bedsuperstructure.

The means for movement of the foot part 39 and 40 of the patient supportsurface 36 is designed in an analogous manner. The motor 53, which isalso arranged inside the housing 35, turns a lead screw, which extendsthrough a nut, which is connected with a tube 54. At the other end ofthe tube 54 one arm 55 of a two-armed lever is attached, whose otherlever arm 56 has its end 57 bearing against the lower side of the part39, which faces the middle part 38 of the patient support surface 36, ofsuch-patient support surface 36. The two-armed lever 55 and 56 ispivoted for turning about a pin 58. The connecting rod 59 is joined atone end with the pivot pin 58 and at its other end is connected with theelectric motor 53.

As shown in FIGS. 1 and 4, all electric motors M1, M2, 41 and 53 arearranged inside the same water-tight housing 35. As already describedsupra, such housing 35 is connected with the transverse member 17. Sincethe housing 35 and with it the electric motors M1, M2, 41 and 53together with the bed superstructure move upward and, respectively,downward, the adjustment of the head part 37 and of the foot part 39 and40 of the patient support frame is possible without any difficultiesusing the associated electric motors 41 and 53 to reach any desiredheight setting of the bed superstructure 2.

As shown in FIG. 2, the distance of the casters 12 from one another islarger than the distance between the telescopic guides 13 and 14 or,respectively, the distance between the telescoping rods 15 and 16. Thetelescopic guides 13 and are accordingly arranged in the cladding, 10with the casters 12 and the recesses 60 provided for them. Accordinglyit is possible so reduce the overall height necessary for the cladding10. The telescopic guides 13 and 14 may consequently reach aconsiderable distance downward and almost as far as the floor 61, onwhich the casters 12 rest.

All electric motors M1, M2, 41 and 53 are able to be operatedindependently from each other. Since the electric motors M1 and M2 areable to be operated independently from each other, the bedsuperstructure 2 may be set obliquely as depicted in FIG. 1. The bedsuperstructure 2 is pivotally mounted on the foot end of the bed aboutthe pivot pin 62. The pivot pin 62 is connected with the transversemember 17. It can be constituted by horizontal extensions, which areprovided at the lower ends of side parts 63 (see also FIG. 2) connectedwith the transverse member 17.

At the head end the bed superstructure 2 is pivotally mounted in asimilar manner about a pivot pin 64 provided on the transverse memberhere. For compensation of the change in length on pivoting the bedsuperstructure 2 in relation to the horizontal setting on the pivot pin64 an upwardly directed pivot lever 65 is pivoted, whose top end ispivoted on the side part 3 of the bed superstructure 2 about a pivot pin66.

Vertical adjustment of the head end of the bed superstructure 2 isreliably provided in the case of the slope indicated in FIG. 1 as well,since the toothed belt 32 will transmit force from the belt pulley 31 tothe gear wheels 33 even in the sloping position.

There are seals between the output shafts of the motors M1 and M2 andthe housing 35, which may be a plastic housing. All drive motors aresupplied from a battery or an accumulator, which is also arranged insidethe housing 35. A built in transformer is not required so that thedisadvantages accompanying same (heating effect, radiation, connectionwith the electrical supply) will not occur. The hospital bed iscompletely free of the supply line voltage. If an accumulator isutilized, it can be charged using a battery charger, which is locatedoutside the bed and is not connected with the bed, for example socketmounted charging device with a rating of for example 15 VA, which can beconnected with the hospital bed for charging up only occasionally.

All casters 12 are able to be locked or, respectively, arrested using asingle arresting device, which is able to be operated from either sideof the bed using the pedals 67 as shown in FIG. 3. The pedals 67 areconnected with a first brake rotary shaft 68, by which the casters 12 atthe foot end of the bed can be arrested. Transmission of force to thehead part is performed by means of a brake rotary rod 69, which isaccommodated in a frame connection 11. The brake rotary rod 69 isconnected with the brake rotary shaft 70 in the cladding 9 at the headend of the bed.

If no oblique setting (Trendelenburg setting) of the bed superstructure2 is desired, the bed frame is to be moved upward or, respectively,downward into the horizontal setting. Accordingly a device forsynchronization of vertical movement of the head part and of the footpart is provided. The telescopic tube 15 or 16 or the transverse member17 is connected with a control device 71. The control device 71 islocated at a distance a from the telescopic tubes 15 and 16, or thelongitudinal axes thereof.

On the. bed superstructure 2 or on one of its side parts 3 two abutmentelements 72a and 72b are arranged at a distance b from the telescopictubes 15 and 16, i. e. the longitudinal axes thereof. The abutmentelements 72a and 72b are arranged one over the other. They have avertical distance c between them.

The housing of the control device 71 is attached to a connecting rod 73which extends from the transverse member 17 to the outer foot end of thebed. A resilient indicating element 74 extends from the housing of thecontrol device 71 toward the middle of the bed. When the bedsuperstructure 2 is in a horizontal setting (see FIGS. 5 and 6) theinner end of the resilient indicating element 74 will be exactly in themiddle between the two abutment elements 72a and 72b.

When the bed superstructure 2 is inclined, the setting of the indicatingelement 74 will not change. Accordingly the setting of the resilientindicating element 74 will initially remain unchanged. The bedsuperstructure 2 is however slanted in relation to the connecting rod73, the control device 71 and the resilient indicating element 74.Therefore, dependent on the direction of slant, either the lowerabutment element 72a or the upper abutment element 72b will strikeagainst the inner end of the resilient indicating element 74. When thebed superstructure 2 is further sloped, the resilient indicating elementwill accordingly be moved upward or downward. Consequently one of thetwo switches 75a and 75b provided in the control device 71 will beoperated. The switch 75a is located underneath the resilient indicatingelement 74, whereas the switch 75b is placed above this resilientindicating element 74. The resilient indicating element 74 is connectedwith an actuating part 76, which extends past the resilient indicatingelement 74 to either side in the vertical direction. The ends of theactuating part 76 engage switch elements 77a and 77b which areconsequently switched over in a manner dependent on the direction ofmovement of the resilient indicating element 74.

The control device causes that drive motor to be stopped which isdriving the part of the bed superstructure 2 which is leading in therespective direction of motion. If for example the bed superstructure 2is slanted in the fashion illustrated in FIG. 1, and if the bed frame isto be moved upward, the control will have the effect that only the motorM1 will run and that the motor M2 is stopped. Accordingly only the headpart, depicted in FIG. 1 on the left, of the bed will be moved upward.This will take place until the bed superstructure 2 is horizontal. Asfrom this time onward both motors will be run so that the bedsuperstructure 2 is moved upward in the horizontal setting.

If the bed superstructure 2 is inclined as shown in FIG. 1 and if it isto be moved downward, the control device 71 has the effect that theelectric motor M1 is halted so that the vertical setting of the head endof the bed is not changed. Furthermore the control device 71 has theeffect that the motor M2 is operated to produce a downward movement sothat the foot end of the bed superstructure 2 is moved downward. Thiscontrol effect is maintained until the bed superstructure 2 is in ahorizontal setting. As from this point both motors are operated to causea downward movement of the bed superstructure.

If the bed superstructure 2 is slanted in the opposite manner to thatillustrated in FIG. 1, that is to say if the head end is in the uppersetting and the foot end is in the bottom position, a suitably reversedcontrol effect is produced. Instead of stopping one motor, such motormay just be run at a lower speed. It is possible furthermore, instead ofhalting one motor to cause such motor to go on running at the same speedand to cause the other motor to run with a suitably higher speed.Furthermore the above mentioned possibilities may also be combined witheach other. The simplest control is however produced if the drive motor,which is driving the part of the bed superstructure leading in therespective direction of motion, is halted and if the other drive motoris caused to run without any change in the speed thereof.

One possible circuit diagram for such a control device is depicted inFIG. 7. The motors M1 and M2 are suitable for counter-clockwise andclockwise rotation and are able to be reversed. The two motors may beoperated separately for upward or downward movement. They may also beoperated jointly for sloping movement in the upward or in the downwarddirection. When the motor M1 is moved for causing upward movement theswitch M1↑ is actuated and when the motor M1 is to be operated forcausing downward motion, the switch M1↓ is operated. In an analogousfashion the motor M2 can be operated to cause upward or downwardmovement by operating the switch M2↑ or M2↓.

If both motors are to cause upward motion, the switch "M1+M2↑ " isoperated. If both motors are to cause downward motion, the switch"M1+M2↓ " is operated.

All switches are connected on one side with the plus wire of a powersupply. The other side of the switches is connected in the mannerindicated in FIG. 7--partly via one or more diodes D7 through D10--withone or more of relays RL1 through RL4. Moreover the switches foroperation of the motors M1 and M2 to cause movement in the samedirection are joined via the diodes D5 and D6 with a further relay RL5,which opens on actuation of the switches C1 and C2. By opening theswitches C1 and C2 the range with the diodes D1 through D4 and theswitches N.O. and N.U. is activated. Instead of having switches it isalso possible to provide reed contacts, photoelectric detectors, FET'sor other sensors. The double switch N.O. (for upward motion) and N.U.(for downward movement) in FIG. 7 corresponds to the switches 77b and77a in FIG. 6. The circuit parts with the double switches N.0. and N.U.and the diodes D1 through D4 ensure that that one of the drive motors M1and M2 is halted, which is driving the part of the bed superstructurewhich is leading in the respective direction of movement.

The caster 102 indicated in FIGS. 8 and 9 is connected with thebedstead. The caster 102 is able to be moved into a first setting(wheeling along) in which it is freely rotatable and into a lockedsetting in which it is locked or braked. In the freely wheeling settingthe caster 10 is able to be freely rotated both about the horizontal pin151 and also about the vertical pin 152.

The caster 102 is arranged on a caster housing 153, which has a shaft132 extending through it. As shown in FIG. 9, the shaft 132 possesses ahexagonal cross section. The caster 102 is set in position by rotationof the shaft 132. If the shaft 132 is in the position "0" indicated inFIG. 9 on the right in the cross section, it is able to be freelyturned. By rotation of the shaft 132 counter-clockwise into the settingmarked "B" the caster is caused to be locked.

Furthermore the shaft 132 may be moved by clockwise turning into thesetting "G" for straight ahead movement of the bed. In this setting acaster of the bed is moved into a setting, in which it is able to bewheeled along while remaining fixed in direction. In this setting freeturning of the caster about the horizontal pin 151 is possible. Rotationof the caster about the vertical pin 152 is however locked in such amanner that the horizontal pin 151 extends perpendicularly to thelongitudinal axis 121 of the bed so that the caster points in thelongitudinal direction of the bed. The other casters of the bed are ableto rotate freely, i. e. both about the pin 151 and also about the pin152. Accordingly steady forward movement straight ahead of the bed isensured.

The rotation of the shaft 132 and accordingly the setting of the casters102 is performed by the motor 134. This motor 134 is designed in theform of a push or traction motor. The motor rod 131 connected with themotor 134 and moved by it is able to be moved in the direction of thedouble arrow 154. It is connected in an articulating fashion with themotor 134 by means of the pin 134a. The other end of the motor rod 131is connected by the pin 155 with a flange of the hub 135 in anarticulating manner.

Projections 156 are arranged on the shaft 132 with a spacing betweenthem, against which disks 157 and 157' bear. On the caster housing 153indicated on the left in FIG. 9 there bears a first hub 135. Between thefirst hub 135 and the other disk 157' a second hub 138 is provided,which has a ledge 158, against which a compression spring 136 bears,whose other end bears against the disk 157'. The hubs 135 and 138 haverecesses in their facing sides, in which rolling bodies 137 in the formof balls lie. Owing to the resilient loading by the compression spring136 the hubs 135 and 138 are braced toward one another.

The first hub 135 is not connected with the shaft 132 in such a manneras to prevent relative rotation. The second hub 138 is connected withthe shaft 132 in such a manner as to prevent relative rotation whilehowever allowing for axial displacement.

The double pedal 133 is connected with the shaft 132 in such a manner asto prevent relative rotation and axial movement. It possesses actuatingmembers 159 at its ends, for example manufactured of rubber or providedwith a rubber casing. By thrust against the actuating members 159 theshaft 132 may be shifted manually or using the foot. On actuation of theshaft 132 by the motor 134 the pedal 133 will move as well so that sothat the respective setting of the casters 102 will be indicated by it.

The hubs 135 and 138 together with the rolling bodies 137 and thecompression spring constitute a clutch. During normal operation thethrust of the motor rod 131 will be converted into a rotary movement ofthe firstly hub 135 about the shaft 132. This rotary motion istransmitted via the rolling bodies 137 to the second hub 138, which forits part transmits it to the shaft 132.

On operation of the shaft 132 by the pedal 133 the clutch in the form ofthe hubs 135 and 138 is disengaged. In this case the first hub 135 is infact locked by the motor 134 and the motor rod 131. The torque exertedby the pedal 133 on the shaft 132 and which is transmitted to the secondhub 138, is larger than the torque able to be transmitted by the rollingbodies 137 so that the rolling bodies 137 emerge from their recesses andmove the second hub 138 against the force of the compression spring 136away from the first hub 135. The second hub 138 can then move inrelation to the first hub 135. During such rotary movement it willentrain the shaft 132 along with it with the result that the caster 102is changed in its setting.

In the case of the modified embodiment illustrated in FIGS. 10 and 11the transmission of force from the motor 140 to the first hub 139 is notvia a motor rod, 131 but rather by means of a worm wheel drive, whichcomprises a worm 141 driven by the motor 140 and a worm wheel in meshtherewith and formed on the first hub 139. The hub 135 of the embodimentof FIGS. 8 and 9 is accordingly replaced by the hub 139, which at thesame time is designed as a worm wheel or a worm wheel segment.

The setting of the shaft 132 is detected by means of a switch, notillustrated in the figure, or by sensors, which supply signals to themotor 134 or, respectively, 140, when the respectively desired switchsetting is reached. Preferably three switches or sensors for the threeswitching positions O, B and G are set by means of the first hub 135 or,respectively, 139. The clutch may however be designed in some othermanner, as for example in the form of radially disconnectable rollingbodies.

In the embodiment the disengagement function of the clutch is created byhaving axially disengeable rolling bodies or balls.

The modified embodiment of the hospital bed depicted in FIG. 12 through14 possesses a bedstead with casters 102 and a bed superstructure, notillustrated in the figures, mounted for vertical adjustment in heightthereon, having a preferably adjustable bed frame. The bedsteadcomprises a first cast housing 101 at the foot end of the bed, a secondcast housing 101' at the head end of the bed and furthermore a firstconnecting tube 106 and a second connecting tube 106'. The connectingtubes 106 and 106' extend at respectively the same height parallel toone another with a spacing between them. They extend furthermoresubstantially perpendicularly to the cast housings 101 and 101' orrespectively perpendicularly to the line connecting two respectivecasters 102 of a cast housing. The connecting tubes 106 and 106'furthermore extend symmetrically in relation to the longitudinal centeraxis 121 of the bed.

In the middle of the cast housing 101 two vertical telescopic guides 104and 104 are arranged extending substantially over the full height of thecast housings 101 and 101'. The cast housings 101 and 101' are, see moreespecially FIG. 13, in the region between the telescopic guides 104 and104' lower than these telescopic guides by the amount d. The recess soformed and generally trapezoidal in shape is able to accept componentsconnected with the bed superstructure during lowering of the bedsuperstructure and projecting downward, as for example components whichare necessary for changing the position of the patient support frame.The telescopic guides 104 and 104' possess a circular cross section asindicated in FIG. 14. However, other cross sections would also bepossible.

In the telescopic guides 104 and 104' a respective telescoping rod 105and 105' is able to run longitudinally. At the upper ends of thetelescoping rods 105 and 105' a bridge 113' is attached, with which thebed superstructure, not illustrated in the figure, is connected. In themiddle of each telescopic guide 104 and 104' a respective lead screw 112is provided whose lower end is axially fixed in the floor 171 of thehousing 101' while being able to rotate therein.

The telescoping rod 105' (and also the other telescoping rods) which aredesigned in the form of telescoping tubes, has at its lower end a leadscrew nut 111, accepting the lead screw 112 in it. Rotation of the leadscrew 112 will cause a movement of the lead screw nut 117 downward and,respectively, upward.

In this respect the lead screw nut 111 is held to prevent it rotatingsince the telescoping rods 105 and 105' respectively connected with anut are for their part joined together by the bridge 113'.

At their lower ends the two lead screws 112 in the cast housing 101'each possess a belt pulley driven by a toothed belt. The toothed belt172 is driven by a drive motor 173. It is trained around variousdifferent bend pulleys and the pulleys of the two lead screws 112 and isin the form of a crossed toothed belt. The drive shaft of the drivemotor 172 extends horizontally (parallel to the longitudinal axis 121 ofthe bed). Owing to the crossed arrangement of the toothed belt it ispossible for both the two pulleys rotating about a vertical axis on thelead screws 112 to be driven by one drive motor 173 and a circulatingbelt 172.

Since the telescoping rods 105 and 105' at the head end and the foot endof the bed may be extended to different extend, length compensation ofthe points of attachment bed superstructure is necessary. At the footend the bed superstructure is on the rotary bearing which is arranged atthe ends of the bridge 113. The bridge 113' at the head end of the bedhas rotary pitmans 115 at its ends, on whose lower ends perpendicularlyextending, horizontal bearers 116 are provided, on which the bedsuperstructure rests adjacent to its head end. Owing to the rotarypitmans 115 length compensation is rendered possible for differentdegrees of extension of the telescoping rods 105 and 105' (if the bed isin the so-called "Trendelenburg" position).

The cladding parts designed in the form of cast housings 101 and 101'are shut off on all sides. All components necessary for actuation of thetelescoping rods 105 and 105' and for changing the position of thecasters 102 are arranged in the interior of the cast housing 101 and101'. The second force transmitting element 107, which is constituted bya shaft, is arranged in the connecting tube 106.

As shown in FIG. 14 the telescoping rods and the telescopic guides 104and 104' are outside the connection line between the associated casters102. The casters 102 of the cast housing 101 are connected together bymeans of the shaft 132. The straight shaft 132 is on the straight linesconnecting the casters 102. To ensure that this shaft 132 does nothinder the movement of the telescoping rods, the telescoping rods andwith them the telescopic guides 104 and 104' are arranged clear of theshaft 132. In this respect the shaft 132 or, respectively, theconnecting line between the casters 102 is on the side facing away fromthe middle of the bed of the telescoping rods or, respectively, thetelescopic guides 104 and 104'. The same applies for the other casthousing 101'. In order to produce the offset between the shaft 132 andthe telescoping rods or, respectively, the telescopic guides 104 and104', the cast housing 101 (and for this matter the cast housing 101')is set at an angle which in the embodiment of the invention in FIGS. 12through 14 amounts to approximately 15°.

The shaft 132 is fixedly attached to a lever, which in terms of FIG. 13projects to the rear, connected in an articulating fashion with avertical connecting level 181. The vertical connecting lever 181 has itsupper end connected with a horizontal connecting lever 182 in anarticulating manner, the other end of such lever 182 being fixedlyconnected with the second force transmitting element 107 in the form ofa shaft. It is in this manner that rotary movement of the shaft 132 isconverted into a rotary movement of the shaft 107. At the other end ofthe shaft the same lever mechanism is provided in order to convert therotary motion of the shaft 107 into a rotary motion of the further shaft132.

The above mentioned casters 102, which can be braked, are available fromColson Castors Limited, Hingley Road, Hallesowan, West Midlands B63 2RR,England, part order number 255 124 090 201 42. The caster 102, which maybe additionally set in the straight ahead travel setting, is availablefrom the same company, order number 255 134 090 401 42. Both types ofcasters are also available from TENTE-ROLLEN GmbH & Co., ofHerrlinghausen 75, 42929 Wermelskirchen, Germany.

We claim:
 1. A bed having a bedstead and having casters and a bedsuperstructure mounted in the bedstead in a vertically adjustablemanner, with an adjustable bed frame comprising, part of the bedsuperstructure provided respectively with at least one telescoping rodwhich runs in an associated telescopic guide of the bedstead, a housingencircling the telescopic guide of the bed superstructure part, thehousing being self-supporting, the housing being shut off on all sides,casters within the housing, and components for the telescoping rodwithin the housing.
 2. The bed as claimed in claim 1, characterized inthat the housing is an injection casting selected from a group includingaluminum and magnesium.
 3. The bed as claimed in claim 1, furthercomprising a head end for the part and a foot end for the part, saidhead and foot ends each being housed and said housing being connectedtogether by at least one connecting part, the connecting part being inthe form of a connecting tube.
 4. The bed as claimed in claim 3,characterized in that the connecting part has a force transmittingelement and casters set in said force transmitting element.
 5. The bedas claimed in claim 1, characterized in that the bedstead castersestablish a line therebetween, and the telescoping rod being clear ofthe caster established line.
 6. The bed as claimed in claim 5,characterized in that the housing is angled in terminal parts thereof.7. The bed as claimed in claim 1, characterized in that the part isprovided with respectively two parallel, spaced telescoping rods, whichare movable in associated telescopic guides of the bedstead, andcasters, the casters spaced apart a distance that is greater than thespacing for the telescopic guides.
 8. The bed as claimed in claim 7,characterized in that the telescoping rods of the head part areconnected together by a respective transverse member.
 9. The bed asclaimed in claim 7, characterized in that the telescoping rods areprovided each with a lead screw drive and a common toothed belt fordriving the lead screw drive.
 10. The bed as claimed in claim 7,characterized by a locking element for locking the casters.
 11. The bedas claimed in claim 10, characterized in that setting members arearranged in the housing.
 12. The bed as claimed in claim 11 having amotor for driving the setting members.
 13. The bed as claimed in claim10, characterized in that the setting members are arranged in thehousing.
 14. The bed as claimed in claim 7, characterized in that thetelescopic guides extend substantially over the full height of thehousing and the housing between the telescopic guides is lower than thetelescopic guides by a predetermined amount.
 15. The bed as claimed inclaim 7, characterized in that the telescoping rods of the foot part areconnected together by a respective transverse member.
 16. The bed asclaimed in claim 7, characterized in that the telescoping rods of thehead part and the foot part are connected together by respectivetransverse members.
 17. The bed as claimed in claim 1 having casters,the casters being adapted to be moved into a first position in whichthey are able to be freely turned and in a second position in which theyare locked.
 18. The bed as claimed in claim 17, characterized in that atleast one caster is able to be moved into a third position in which thecaster can be turned but keeps to a given set direction.
 19. The bed asclaimed in claim 20, characterized by an actuating part for manuallychanging the setting of the casters.
 20. The bed as claimed in claim 19,characterized by having an actuating part and a first force transmittingelement connected with the actuating part.
 21. The bed as claimed inclaim 20, wherein said first force transmitting element furthercomprises a shaft.
 22. The bed as claimed in claim 18, characterized inthat a first force transmitting element is connected with two casters.23. The bed as claimed in claim 18, characterized in that the part ofthe bed has a head end and a foot end, each have a respective casterwhich casters are connected together by a first force transmittingelement and in that the two first force transmitting elements areconnected together by means of a second force transmitting element. 24.The bed as claimed in claim 23, wherein the force transmitting elementsfurther comprise shafts.
 25. The bed as claimed in claim 18, furthercomprising a shaft for a first force transmitting element.
 26. The bedas claimed in claim 17, having a motor and in which the casters aremovable into a third position in which the casters can be turned butkeep to a given set direction.
 27. The bed as claimed in claim 1,characterized in that the housing is angled in its terminal parts.